This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Elevated night-time blood pressure and an abnormal night-time decline in blood pressure (non-dipper pattern) have recently been recognized as important problems in children with renal transplants. These entities have been associated with kidney function decline, increased urine protein, cardiovascular events and death. The study objective is to investigate the effect of specific timing of blood pressure medication on night-time blood pressure in pediatric renal transplant recipients who are non-dippers. Two clinical trials, each with 14 treatment subjects and 14 controls, will run in parallel. One trial will examine the effect of shifting a single blood pressure medication from morning to evening hours. The other will examine the effect of adding a blood pressure medication in the evening. Blood pressure will be measured by 24 hour ambulatory blood pressure monitoring at baseline, 3 months and 6 months after the medication change. In addition, the effect of the medication change on heart wall thickness, artery stiffness, kidney function and urine protein excretion will be determined. These data will provide the foundation to improve cardiovascular and renal outcomes in this high risk population.